Spring element for seating structure



May 22, 1962 M. STUBNITZ 3,035,828

SPRING ELEMENT FOR SEATING STRUCTURE Filed Aug. 4, 1958 INVENTOR MAUFRl CE. STUBNITZ BY $3M ATTORNEY United States Patent Oflice 3,635,828 Patented May 22, 1962 3,035,828 SPRING ELEMENT FOR SEATING STRUCTURE Maurice Stuhnitz, Adrian, Mich., assignor to Stubnitz Greene Corporation, Adrian, Mich, a corporation of Michigan Filed Aug. 4, 1958, Ser. No. 752,828 Claims. (Cl. 267-110) The invention relates to improvements in resilient seat and back construction, being particularly adapted for use in furniture such as chairs, sofas, hassoeks, etc.

More specifically, the invention resides in an improved spring wire structure comprising a plurality of arched wire members having Z-shaped torsion bars at their ends and disposed in spaced parallelism with their opposed ends disposed in hinged relation with spaced opposed suppont portions.

The invention has particular advantage in the manufacture of furniture using wooden frames for the reason that no stress is placed upon the wooden frames except during the period when the spring wire structure is supporting a load. This arrangement relieves the tendency of wood frames to warp or pull in and obviates the necessity of using numerous cross struts to keep the wooden frames in proper shape.

It will also become apparent from the illustrated embodiment of the invention that the simplicity and ease of application of the spring elements makes them readily adaptable to all kinds of seating structure from the simplest stool or hassock to the more intricate and expensive chairs and sofas.

Thus, an object of the invention is to provide a novel spring wire element for seating structure in the form of an arch having transverse torsion bar portions at opposite ends to provide end supports for the arch, the bar portions having angular hinge and anchor extensions received Within the support structure.

Another object is to provide an improved spring wire element for seating structure in the form of a Z-shaped arched tension member.

A further object is to provide a seating structure in the form of a frame having spaced opposed sides and spring wire elements bridging said frame, the elements being in the form of arched linear wire portions having the tension portions generally disposed normal to the plane of deflection of the arched portion and resting upon the frame, the tension portions having turned hinge and anchor portions extending into the frame to permit the torsion portion to hinge in a plane substantially normal to the plane of deflection of the arched portion and to hold one end of said torsion bars against torsional rotation about their longitudinal axis relative to the frame.

A still further object of the invention is to provide a seating structure of spring wire elements in which the elements are unstressed in a non-load supporting state and an arched linear spring portion has a torsional as well as a hinged association with the frame structure whereby the cordal length of the arched spring between its points of support is capable of being varied in a novel manner and stability under load is provided.

These and other objects and advantages residing in the present invention will appear from the following specification and the appended claims.

In the drawings,

FIG. 1 is a fragmentary perspective view of a seating structure embodying the present invention for Wooden frames,

FIG. 2 shows a modified form of the invention applied to a tubular frame, and

FIG. 3 shows a modification of FIG. 2 applied to an angular frame.

In FIG. 1 is shown a seating structure having a wooden frame 12, a suitable pad 14 carried by an insulator 16 and a cover 18. The resilient support for the pad 14 and insulator l6 takes the form of a plurality of spring wire elements 20 arranged in parallelism and bridging the spaced opposed sides of the frame 12.

As illustrated, the elements 20 have a preformed arch portion 22, preferably of substantially straight form in contrast to so-called zig-zag or sinuous wire elements now being extensively used in furniture. At opposite ends of the arched portion 22 of each spring element 29 are integral torsion bar portions 24 which rest upon the surface of the frame 12. Lateral extensions 26 upon the torsion bars 24 are received in suitable socket means such as holes 28 defined in the frame 12 and provide a non-rotational connection with respect to torsional stresses exerted upon the torsion bar portions 24 as well as a hinge point for one end of the torsional bar portions 24.

It will be readily appreciated that when the spring element 20 is loaded that there will be a tendency for the cordal length of the arch to increase with the torsional bar extension 26 hinging in the holes 28. Also, when the elements 2% are loaded torsional stresses will be developed within the torsion bars 24 such stresses being resisted by the anchorage of the extension 26 within the holes 28 of the frame. Under no load, because the elements 20 are preferably pre-formed, no stresses are bearing upon the frame 12 tending to warp or pull in the sides of the frame 12. Under load, the Z-shape of the wire spring elements, as viewed in plan view, adds greatly to the stability of the elements by resisting any tendency to roll or be displaced sidewise. The hinge action of the elements 20 about the longitudinal axis of the extensions 26 permits the use of a linear spring for the arched portion 22 of the spring element as the effective length of the spring is able to vary to support the load conditions. [it will be understood that when the cordal length of the arch 22 is increased or decreased that the torsion bars 24 will hinge about the extensions 26 and preferably the torsion bars 24 are resting upon the surface of the frame 12 and will move over the surface as the cordal length of the arch 22 varies.

in FIGS. 2 and 3 is shown the manner in which the spring element 20 of FIG. 1 may be adapted to other forms of supporting frames. A tubular frame 36 is shown in FIG. 2 having holes 32 to receive the L-shaped extension 34 of the torsion bar portion 36. To compensate for the thin wall of the frame 30, the extension 34 has a turned foot 38. In PEG. 3 the spring structure of FIG. 2 is shown adapted to an angular frame 40 having holes 42 in one flange thereof.

Having thus described my invention what I claim is novel and desire to protect by Letters Patent is:

l. A seating structure comprising a frame having spaced opposed portions, spring wire elements bridging said portions, said elements being in spaced parallel arrangement, each element consisting of a bridging portion, integral lateral torsion bar portions having a direct junction with opposite ends of said bridging portion and providing the supporting bases therefor and resting upon said frame portions, lateral extension portions having a direct junction with said torsion bar portions having a hinge and anchor connection with said frame portions to permit said torsion bar portions to hinge in a plane substantially normal to the plane of deflection under load of said bridging portion, said extension portions being sub stantially parallel to said plane of deflection, the connection between said bridging portion and said frame portion other than said lateral extension being a sliding connection upon surfaces of said frame.

. In a seating structure, spaced frame portions, a

. a plurality of spring wire load supporting elements, said elements being Z-shaped with lateral torsion bar portions disposed at opposite ends and upon opposite sides of an arched load supporting portion, said torsion bar portions having lateral extensions for hinging and torsion resisting anchorage, said lateral extensions being substantially parallel to the plane of deflection of said arched portions under load, and socket means in said frame portions in which said last lateral extensions are received for hingedly supporting said torsion bar portion and for resisting torsional stresses placed thereupon when said arched portions are loaded.

3. In a seating structure, spaced frame portions, a plurality of spring Wire load supporting elements, said elements having lateral torsion bar portions disposed at opposite ends of an arched load supporting portion and having their longitudinal axes disposed substantially normal to the plane of deflection of said elements under load said torsion bar portions having lateral extensions disposed substantially parallel to said plane for hinging resisting anchorage, and socket means in said frame portions in which said last lateral extensions are received for hingedly supporting said torsion bar portions and for resisting torsional stresses placed thereupon when said arched portions are loaded.

4. In a seating structure, spaced frame portions, a resilient load supporting element bridging said frame portions and resting thereon for relative sliding movement, said elements having a bridging portion, L-shaped torsion bars and hinge portions at opposite ends of said bridging portion, said torsion bars having their longitudinal axes disposed substantially normal to the plane of deflection of said elements under load and said hinged portions being disposed substantially parallel to said plane and socket means in said irame portions to receive the ends of said L-shaped portions most removed from said bridging portion to hingedly support said bridging portion and to resist torsional stresses.

5. In a seat structure as defined in claim 4 wherein said torsion bars and hinged portions are located on opposite sides of a longitudinal axis of said element.

References Cited in the file of this patent UNITED STATES PATENTS 2,622,661 Markle Dec. 23, 1952 2,719,578 Flint Oct. 4, 1955 2,870,823 Staples Jan. 27, 1959 

